Tiny harvesters power intelligent aircraft bodies

Kate Taylor, 14th June 2011

Airplane designers have been working on sensor networks something like the human nervous system, which would run throughout the body shell and report directly to engineers when maintenance is required.

Even the tiniest collisions can easily lead to damage in the body of the aircraft - and on planes made of modern carbon materials, in particular, this can be difficult to spot. With suitable sensors connected directly to the body of the aircraft, this could be constantly monitored.

But these sensor networks will need power - and a team at EADS Germany and the Vienna University of Technology has now developed a way of powering them for free.

The trick, says the team, is to generate electricity from the temperature difference between the icy cold air in high altitudes and the air close to the ground. Each individual sensor has a thermoelectric generator with a small water tank, storing thermal energy.

"From the temperature difference between the exterior and the interior, we can harvest energy for the sensor element, using a thermoelectric generator," says Dominik Samson of EADS.

During landing, the process works in reverse, with the plane heating up again and the inner part of the module remaining cold – and again, electricity can be produced.

"A plane has a durability of roughly thirty years," says Samson. "If the sensors were operated with batteries, each of them would use up about one hundred batteries during this time."

And the technology could even help out cabin crew, says the team.
Sensors could monitor whether passengers have fastened their seatbelts, or whether tables are in an upright position. Cebin crew call buttons wouldn't need expensive and complicated wiring, just the body heat of passengers.

"The first and most important step has been taken," says TU Vienna's Ulrich Schmid. "We are confident that this wireless sensor technology will travel on board many airplanes soon,"